Development and reduction of synaptic potentiation induced by perforant path kindling

The effects of perforant path kindling on perforant path-dentate synaptic transmission and on granule cell excitabilities were examined by the field potential recording technique in freely moving rats. Both population EPSPs and population spikes continued to increase 1 h after the first kindling stimulation and thereafter, and the potentiation of the population EPSP attained 149% of the prekindling control value. Cumulative effects of the kindling stimulations on the population EPSP, however, were rarely observed and the population EPSP, potentiated by the first few kindling stimulations, decreased gradually in the later stage of kindling. In some animals, the amplitude of the population spike sustained a highly potentiated value in the later kindling period in spite of the decrease in the population EPSP. Even in animals that showed a reduction in both population EPSPs and population spikes in the later kindling period, an enormous population spike, which we refer to as the “outbreak of the giant population spike”, was sometimes evoked suddenly without corresponding changes in the population EPSP. These results indicate that an abnormal hyperexcitability of the granule cell was produced by the kindling stimulations. Furthermore, the polysynaptic potential presumably produced through the recurrent excitatory hippocampal-entorhinal circuit was observed to increase after kindling. The significance to kindling, and the possible mechanisms of the abnormal hyperexcitability of postsynaptic neurons may be related to a change in brain norepinephrine concentration and its influence on the membrane potential.     

河北健康汉族人群GSTO2基因多态性研究

目的探讨河北汉族人群谷胱甘肽硫-转移酶O2(GSTO2)基因多态性的分布情况。方法应用聚合酶链式反应-限制性酶切片段长度多态性(PCR-RFLP)方法对210例河北汉族正常人进行GSTO2N142D和GSTO2 A183G基因多态性分析。结果河北汉族人群GSTO2 N142D和GSTO2 A183G基因多态性符合Hardy-Weinberg遗传平衡定律。河北汉族人群GSTO2 N142D基因型频率分布和等位基因频率分布与贵州汉族人群、台湾地区人群、泰国人群、伊朗人群、意大利人群、美国人群有显著差异(P0.05)。河北汉族人群GSTO2 A183G基因型频率分布与台湾地区人群、德国人群、美国人群有显著差异(P0.05),而与日本人群无显著差异(P0.05);但其等位基因频率与台湾地区人群、日本人群、德国人群、美国人群有显著差异(P0.05)。结论河北汉族人群GSTO2基因存在多态性,具有特异性。     

中山市流动人口与户籍人口自杀率和自杀方式特征分析

目的分析2015年-2017年中山市流动人口和户籍人口自杀率变化趋势和自杀案例特征,为中山市制定自杀干预策略提供参考。方法抽取中山市死因登记报告信息系统中死亡时间为2015年1月1日-2017年12月31日的死亡案例,按照是否具有中山市户籍分为户籍组和流动组,计算并比较两组自杀率和自杀方式的差异。结果中山市2015年-2017年自杀率为4. 03/10万。户籍组和流动组年自杀率分别为3. 61/10万、4. 46/10万。两组自杀率均随年龄增长呈上升趋势,流动组60岁以上人群自杀率高于户籍组(34. 94/10万vs. 6. 83/10万)。前三位的自杀方式,户籍组分别为自缢[95例(53. 67%)]、服用农药[27例(15. 25%)]和高坠[22例(12. 43%)];流动组分别为自缢[65例(30. 37%)]、高坠[48例(22. 43%)]和服用农药[30例(14. 02%)],两组自杀方式分布的差异有统计学意义(χ~2=32. 99,P<0. 01)。结论中山市流动人口与户籍人口自杀死亡的案例均以自缢、服用农药和高坠为主。流动人口自杀率略高于户籍人口,老年流动人口可能是高自杀风险人群。     

The epidemiology of myasthenia gravis in central and western Virginia.

We conducted a study of the epidemiology of myasthenia gravis (MG) in four locations in central and western Virginia from 1970 through 1984. The population surveyed was 555,851 in 1984. A total of 73 new cases of MG occurred during the survey period, producing an overall average annual incidence rate of 9.1 per million. The point prevalence rate in 1980 was 13.4 per 100,000, and in 1984 it was 14.2. Approximately 15% of the population was black, and we found that incidence and prevalence rates for the black population were higher than the corresponding white population. When the population was subdivided into <50 and 50+ age groups, the incidence and prevalence were significantly higher in the older group. The rates we report here are higher than rates reported from any other locality. The reasons for the higher rates include optimal case identification, survey of a population with a higher incidence, and increasing aging of the population.     

Population aspects of the dementias

In the United Kingdom there are some key facts which have implications for policies and services for people with dementia. The first group are to do with older people and their position in the total population. Overall the population of this country is projected to increase, but only by 0.2%. However, within that the population is ageing, i.e. the proportion of older people in the population is projected to increase and the proportion of very old people in the older population is also projected to increase. Also of significance is that the population of working age is projected to decline. Second gender and marital status are important variables. Third is the need to consider where people live. The two important facts here are that the proportion of people living alone is increasing, and expected to grow further, and family patterns are changing. Both of these will have an effect on who is available to care. But we also need to look at the implications of population change in the EU which have implications for the UK. Some of the implications and issues of these population aspects are then discussed.     

The biphasic pattern of age-specific malignant brain tumor mortality rates

Many aging-associated neurologic disorders, including primary malignant brain tumors (MBT), share a common biphasic age-specific mortality rate pattern: initially increasing exponentially with age, and then declining. A modeling study using MBT mortality was conducted to determine if the observed biphasic pattern of MBT age-specific mortality rates emerges if one assumes that there exists a population subset that is inherently susceptible to MBT, and that the risk of mortality from MBT in that susceptible population subset continues to increase exponentially with age. A hypothetical population was subjected to 1988 general mortality risks. A population subset susceptible to MBT was subjected to both exponentially increasing 1988 general and MBT mortality risks. Expected MBT age-specific mortality rates in the total population (both general and MBT susceptible subsets) were determined. Expected MBT age-specific mortality rates in the total population initially increase exponentially with age, and then decline. Moreover, when the size of the MBT-susceptible population subset was set at 1/125 of the size of the general population size, the modeled pattern of age-specific MBT mortality rates closely mimicked the observed pattern of age-specific MBT mortality rates. The observed biphasic pattern of age-specific MBT mortality rates can be explained by the existence of an MBT-susceptible population subset in whom the risk of MBT mortality increases exponentially with age and population subset depletion occurs.     

Prevention of unintentional injury to people with intellectual disability: a review of the evidence

Background Recent research evidence shows that people with intellectual disability (ID) have double the unintentional injury risk of the general population and the risk is further increased in the presence of psychopathology and epilepsy. The pattern of injury and the circumstances surrounding an injury event in those with ID have some similarity with that of young children in the general population. Interventions to prevent injuries are an important health priority in this vulnerable population. This paper reviews evidence from injury prevention studies for people with ID and also considers the relevance of general population injury interventions for this population. Method Information regarding injury prevention in both ID and general populations was identified using online systems and consultation with research and public health organizations. Results Few published studies were identified addressing the issue of injury prevention for those with ID. Possible injury prevention strategies appropriate for the major causes of injury in the ID population were identified from the general population literature. While many environmental injury prevention strategies for young children in the general population are applicable to the population with ID, some may require design modification to ensure effectiveness. Other promising approaches include improved information for parents/carers, primary care physician counselling, and home visits by well‐informed and motivated professionals. There may be injury prevention benefit from improved management of psychopathology and epilepsy. Conclusions The issue of injury prevention for those with ID has not been addressed to the extent that the magnitude of the problem requires. Injury prevention programmes trialling a variety of evidence‐based approaches and strategies are needed to protect the quality of life for the ID population and their families.     

Differential effects of pentobarbital and ether on the synaptic transmission of the hippocampal CA1 region in the rat

The effect of ether and sodium pentobarbital on the synaptic transmission of the hippocampal CA1 region was studied in chronically implanted rats. Animal behavior, EEG, and the average evoked potentials (AEPs) following electrical stimulation of the alveus or the stratum radiatum in the CA1 region were recorded. Components of the AEPs, interpreted previously as generated by population excitatory postsynaptic potentials (EPSPs), population inhibitory postsynaptic potentials (IPSPs) (Leung 1979a, b, c) or population postsynaptic spikes (Andersen et al. 1971), were differentially sensitive to ether or pentobarbital. Ether reduced the population EPSPs and population spike evoked at all intensities tested (1-4 X threshold); the population IPSP was slightly enhanced at intermediate stimulus intensities. Pentobarbital suppressed the population EPSP evoked by alvear stimulation but not that by radiatum stimulation, reduced the population spike and greatly enhanced and prolonged the population IPSP evoked at low stimulus intensities. At high stimulus intensities, the IPSP was interpreted to be smaller after pentobarbital but neuronal output from the hippocampal CA1 region, as seen from the evoked population spike, remained attenuated. It is concluded that ether and pentobarbital both suppress hippocampal neuronal excitability but the effect of anesthesia differs for different anesthetics, for different synapses and for different levels of activity in the input fibers.     

U.S. psychologists' suicide rates have declined since the 1960s

In the 1960s and early 1970s, proportionately more professional women committed suicide than did women in the general population, while professional men committed suicide at rates similar to men in the general population. To provide more recent information, this study explored suicide rates among U.S.-resident American Psychological Association members during the years 1981 to 1990. The suicide rate for women in the Association was found to be 7.6 per 100,000 population per year, a rate that is lower than in the 1960s and similar to women in the general population. The rate for men was found to be 7.8 per 100,000 population per year, a rate that is lower than in the 1960s and lower than among men in the general population. Effects of increasing numbers of women in the professions in general, or in psychology in particular, may explain the decline in suicide rates.     

Epidemiological methods used in studies in the prevalence of Tourette syndrome

Tourette syndrome (TS) prevalence was studied since the early 80-ies. Its clinical course is characterised by co-occurrence of motor and vocal tics. Results of previous epidemiological studies were surprisingly divergent: the prevalence varied from 0.5 to 115 cases per 10,000 population. The disease previously recognised as extremely rare and severe is now considered as quite common, with often moderate course. Selected methods used in studies of TS prevalence and analysis of their possible impact on study results are presented. The studies were divided into 3 groups: studies of the hospitalised population, large-scale screenings and studies involving school population, basing on characteristic and size of population, methods of selection of subjects, diagnostic and screening methods used. Studies of the hospitalised population involved patients with most severe symptoms, in different age groups, different methods of final diagnosis confirmation were used. TS prevalence varied from 0.5 up to 15 cases per 10,000 population. Procedures used in large-scale screening studies made possible the elimination of potential selection bias. Large populations were studied using transparent and repetitive confirmation of diagnoses. Their validity was additionally checked in parallel validity studies. TS prevalence was in the range 4.3 to 10 cases per 10,000 population. The highest TS prevalence was obtained in studies involving schoolchildren. Data were gathered from multiple sources: from parents, teachers and children, as well as from classroom observation. Diagnoses were made by experienced clinicians. TS prevalence obtained in school population studies was between 36.2 up to 115 per 10,000 population.     

Capgras syndrome: possibly more common among the Maori of New Zealand

OBJECTIVE: The report describes an apparently greater incidence of Capgras syndrome among the Maori population compared with the European population, in the most easterly catchment area served by Tauranga Hospital in New Zealand's Bay of Plenty. METHOD: Over the last year we have become aware of five cases of Capgras syndrome in our catchment area. This area (population nearly 21,000) consists of a rapidly expanding new suburb of the city of Tauranga and a rural area extending 55 km east of the city. These figures were compared with those of the westerly catchment area served by Tauranga Hospital, where the psychiatric team is not aware of any examples of Capgras syndrome among their population. The 1996 census figures were obtained in order to calculate a population ethnicity breakdown. RESULTS: Five cases of Capgras syndrome were identified in the most easterly catchment area where 19% of the population identified as Maori, 75% as European and 6% as other or non-specified. All of the cases occurred in Maori patients. This compares with no identified cases of Capgras syndrome in the most westerly catchment area where 12% of the population identified as Maori, 87% as European and 1% as other or non-specified. Four out of five cases were female. Two cases had a history of cannabis use. Three cases had exhibited dangerous behaviour towards family members. CONCLUSIONS: There is an apparently greater incidence of Capgras syndrome among the New Zealand Maori population compared with the European population in the most easterly catchment area served by Tauranga Hospital. In our population Capgras syndrome is a common, not rare, feature of psychotic illness, and the cases support a previously reported association of this syndrome with dangerousness.     

Differences in factors influencing the familial aggregation of febrile convulsion in population and hospital patients

Socio-demographic data, initial clinical manifestations, outcome and family aggregation of febrile convulsion (FC) were compared between 85 population and 364 multicenter patients. More patients presented with clustering of seizures and had recurrence of FC in multicenter group than in population group. Multicenter patients had more fever episodes per year more day-care attendance and a higher incidence of FC history in their parents. The odds ratio of FC in the siblings was 6:1 in population group and 12:1 in multicenter group. Lower socioeconomic status influenced the presence of FC in the sibling of population group. Instead, FC histories in the father and paternal cousins of probands had influence on the presence of FC in the siblings of multicenter group. We conclude that the population FC sample rather than the hospital sample is the more representative. And there are differences not only in the clinical manifestations but also in the effect of environmental and genetic influences on the family aggregation in population and hospital patients.     

Impact of postcensal versus intercensal population estimates on prevalence of selected developmental disabilities--metropolitan Atlanta, Georgia, 1991-1996

Prevalence estimates often use U.S. Census Bureau estimates of the population as denominator data. Postcensal estimates are population estimates produced following a decennial census. Intercensal estimates are surrounded by 2 census years and supersede postcensal estimates. In this report we describe prevalence estimates in Atlanta for mental retardation, cerebral palsy, and hearing and vision loss for 8 year olds from 1991-1994 and 1996. We used calculations of postcensal and intercensal population estimates. Intercensal population data were consistently higher than postcensal data, and prevalence estimates for developmental disabilities were lower using intercensal population data. This discrepancy varied by race and ethnicity. Comparison of population estimates, particularly at state and local levels, should be considered to assess meaningful differences in published prevalence estimates using intercensal data.     

Field-potential evidence for extrasynaptic alterations in the hippocampal CA1 pyramidal cell population during paired-pulse potentiation

The mechanisms of paired-pulse potentiation of the CA1 pyramidal cell population were examined by determining input-output relations for control and potentiated responses originating from the activation of radiatum fibers in the hippocampal slice preparation. Two types of potentiation for synchronously discharging pyramidal cells (population spike) were observed. In the first type, the potentiation of the population spike was found to be a combination of synaptic and extrasynaptic factors. This form of potentiation was observed in 16 of 28 slices. In the second type, the potentiation of the population spike was attributed entirely to the potentiation of summated dendritic depolarizations (population EPSP). This synaptic process of potentiation was observed in 12 of 28 slices. The involvement of only extrasynaptic mechanisms in the paired-pulse potentiation of the population spike was not observed. For the potentiation originating from a combination of synaptic and extrasynaptic mechanisms, 60% of the potentiation of the population spike was a result of synaptic factors and 40% could be attributed to extrasynaptic factors. These results support the concept that alterations in the excitability of postsynaptic neurons serve as a component of the mechanisms of paired-pulse potentiation in the radiatum fiber-CA1 pyramidal cell system.     

Aggression levels in treatment seeking inpatients with alcohol-related problems compared to levels in the general population in Hungary

Association between aggression and heavy alcohol use is documented in the literature in various disparate samples and settings. Comparison of trait aggression levels using a uniform methodology across different samples is almost entirely lacking. This study compared trait aggression levels of treated inpatients with severe alcohol-related problems with those of a nationally representative sample of the general adult population using the same methodology. Results indicated that in the patient population the trait aggression levels were substantially higher than in the general population. Because several studies have demonstrated that aggressive personality traits are closely linked with violence after drinking alcohol, our results further highlight the importance of treatment programs in this at-risk population. From a methodological perspective, the higher trait aggression level of inpatients with alcohol-related problems compared with the general population supports the assumption that the underrepresentation of alcoholics in the population surveys may restrict the range in the severity of alcohol use and dependence, and may therefore produce severely biased results in such studies.     

Cancer and learning disability

This study was performed in order to complete a 60-year survey of the rate of deaths from cancer in a group of people with a learning disability. It was carried out on an in-patient population, and information was obtained from hospital records of deaths and patient medical notes. During the 10–year period studied, 13.6% of all deaths were from cancer, compared to a rate of 26% in the general population. The ratios of different types of cancer were also markedly different to those in the general population, with a very high proportion (55%) being cancers of the gastro-intestinal tract Other types of cancer, such as those affecting the bronchus, breast and prostate gland, which cause death most often in the general population, hardly appeared at all in the in-patient population studied. The present paper explores some of the possible reasons for these findings and the implications for the current research in the wider field of cancer in the general population.     

Differences in the use of substances of abuse by psychiatric patients compared with medical and surgical patients

This paper presents findings from a comparison between patterns of use of substances of abuse among a psychiatric population and among a similarly studied medical and surgical patient population. A self-assessment survey was carried out in an urban, university medical center population that included 300 psychiatric patients and close to 3000 medical and surgical patients. The psychiatric population was significantly higher than the demographically similar general medical and surgical population in quantity and frequency of use, problems associated with use, and composite categories of use of alcohol and other drugs of abuse. This was true in spite of the fact that the psychiatric service did not readily accept known substance-abusing patients at the time the study was conducted.     

Prevalence of inhibitors in a population of 3435 hemophilia patients in France. French Hemophilia Study Group.

A cooperative study between the 37 centers of the French Hemophilia Study Group was undertaken to establish the prevalence of inhibitor patients in the French hemophilia population. The prevalence reported in the literature varies widely from 3.6% to 17.5%. Some of the studies are dealing with a small number of patients and inhibitor patients are reported either to the total number of hemophiliacs or to the severely affected ones. The French study provided information concerning 3,435 hemophiliacs and showed a prevalence of 6.2% for the overall population. Prevalence of inhibitors was found to be 7% in the population of hemophilia A patients and 12.8% in the population of severely affected ones. The prevalence of inhibitors in the population of hemophilia patients was 2% and 4% in the population of severely affected hemophilia B patients. The cooperative study also showed that 47.5% of inhibitors are detected before 10 years of age and that 82% of inhibitor patients are high responders. Analysis of inhibitor detection in patients under the age often showed that there was a peak in the population of 2 years old children. Although not comparable to the present study the high incidence of inhibitors with ultrapurified and recombinant FVIII reported in previously untransfused patient may be borne in mind.     

Optimization of population decoding with distance metrics

Recent advances in multi-electrode recording and imaging techniques have made it possible to observe the activity of large populations of neurons. However, to take full advantage of these techniques, new methods for the analysis of population responses must be developed. In this paper, we present an algorithm for optimizing population decoding with distance metrics. To demonstrate the utility of this algorithm under experimental conditions, we evaluate its performance in decoding both population spike trains and calcium signals with different correlation structures. Our results demonstrate that the optimized decoder outperforms other simple population decoders and suggest that optimization could serve as a tool for quantifying the potential contribution of individual cells to the population code.     

A method for calculating projected increases in the number of dementia sufferers

A new method of projecting increases in the number of dementia cases is described. This method is based on a statistical analysis of all published prevalence studies which shows that prevalence rate rises exponentially with age. The method can be easily applied to any age-specific population projections. When applied to Australia and New Zealand, the method shows that the increase in dementia will greatly exceed the total population growth rate, and even surpass the expected rise in the elderly group over the next third of a century. The method predicts that the Australian demented population will increase by 136-139% between 1984 and 2021, compared to a general population increase of only 42-54%. Over the period 1982 to 2016, the New Zealand demented population will grow by 96-100% against a rise of 18-26% in the general population. The validity of this method and its implication for future service demands are discussed.